A standard mass-production grinding apparatus for annular workpieces has a plurality of grinding stations each provided with a holder that retains and rotates the workpieces and a tool that machines its inner and/or outer periphery. There are at least two such stations with the upstream station provided with a coarse grinding stone and the downstream station with a fine grinding or burnishing stone. The workpieces are delivered to the apparatus by an input device that opens adjacent the upstream station and the workpieces are taken from the apparatus by an output device that receives the finished workpieces from the downstream station.
In order to move the workpieces through the stations it is standard to provide a carousel arrangement as described in German patent documents 1,752,520 of E. Thielenhaus (citing U.S. Pat. Nos. 1,916,916, 2,145,310, 2,773,333, and 2,813,379), 1,752,064 (citing U.S. Pat. No. 2,224,265), and U.S. Pat. No. 1,937,802 (citing U.S. Pat. Nos. 2,842,900 and 2,771,714). This carousel has a plurality of angularly equispaced seats that ar orbited through the successive grinding stations and also past the input and output stations. Thus periodically all the workpieces are advanced one station, with a new workpiece being moved from the input station to the upstream grinding station, the workpiece in the downstream station being moved to the output station, and all the other workpieces being moved down one station.
Such a system is fairly bulky, requiring that the grinding stations be positioned about a common center. This makes the apparatus fairly difficult to operate and work on. In addition if workpiece size changes, the carousel must be changed to one with differently dimensioned seats. This carousel is a fairly bulky and mechanically complex item in itself so its replacement entails quite some down time for the machine.